1. Field of the Invention
The present invention relates to a propellant charge-operated setting tool for driving in fastening elements, such as nails, bolts, pins, etc. . . in a constructional component and including a housing, and a setting mechanism located in the housing and actuated in response to ignition of a propellant charge, which is carried by magazine strip displaceable in the setting tool, for driving in a fastening element.
2. Description of the Prior Art
The propellant charge, which is used in the setting tools of the type described above, is formed as a pill or cartridge of a powder fuel. A plurality of such pills or cartridges is arranged on a magazine strip. Magazine strips are pushed through a feeder provided on a setting tool, with a single charge being received at a time in a cartridge socker. The magazine strip with blisters of pills or cartridges is automatically displaced through the setting tool upon completion of a setting process for placing a new charge in the cartridge socket.
A setting tool of the type described above is disclosed in German Publication DE 199 01 268 A1.
In order to be able to conduct a greatest possible number of setting processes without the replacement of the necessary cartridges, blisters, or magazine strips, there was proposed to use very long magazine strips.
U.S. Pat. No. 4,204,473 discloses a cartridge strip with a large number of propellant charges The cartridge strips are arranged in a magazine box. The cartridge or magazine strips in this magazine box are arranged in layers.
U.S. Pat. No. 6,053,108 discloses an arrangement of pill-shaped charges in a blister or magazine strip, and an arrangement of powder charges in a cartridge strip. The magazine or cartridge strip contains a large number of charges and is unwound along a spiral.
The drawback of the use of such long magazine strips, such as cartridge of blister strips, in setting tools consists in that they make handling of the setting tools very difficult when a large section of the used portion of the magazine strip extends from or is suspended from a setting tool.
Accordingly, an object of the present invention is to provide a setting tool of the type described above in which the drawback of the prior art is eliminated and in which a long magazine strip can be used without adversely affecting handling of the setting tool.
This and other objects of the present inventions which will become apparent hereinafter, are achieved by providing the setting tool with a device for cutting the magazine strip.
The cutting device permits to separate an empty section, of the magazine strip, e.g., of a cartridge or blister strip from a usable section of the magazine strip. The cutting device in this way prevents formation of long empty ends of magazine strip suspendable from the setting tool and which made the handling of the tool more difficult. The cutting devices can be, e.g., of a mechanical type or also include electrical components for control purposes and for an automatic start of a cutting process. The use of a cutting device simultaneously permits to eliminate, in the setting tool, a storage space for the used section of the magazine strip, which otherwise would have been needed and which occupies a large space in the setting tool.
Advantageously, the cutting device has at least one cutting element arranged behind the cartridge socket in the displacement direction of the magazine strip, so that it always cuts the used portion of the magazine strip. Ideally, the cutting element is so arranged that it effects transportation of the magazine strip during the cutting process while severing the magazine strip.
To prevent suspension from the setting tool of non-yet used magazine strip, specific magazine-receiving means is provided in the setting tool in which the magazine strip can be placed.
According to one advantageous embodiment of the present invention, the magazine-receiving means is formed as a magazine comportment displaceable between a first position corresponding to an operational position of the setting tool, and a second position corresponding to a position of the setting tool in which insertion/removal of the magazine strip is possible.
An arrangement of a magazine strip in a magazine or magazine box from which the strip can be pulled out, advantageously insures a reliable support and transportation of magazine strips. Further, an easy handling of the setting tool is also insured.
Advantageously, the cutting element can be mounted on the magazine compartment and be fixedly connected therewith. When the magazine compartment is displaced from the operational position to a removal position, the cutting element is displaced through the displacement path of the magazine strip, cutting off the used portion of the magazine strip, so that the used portion falls out of the setting tool. The magazine compartment functions similar to a drawer which is used for inserting the magazine box into the setting tool and for removal the magazine box from the setting tool. The movement of the magazine compartment is similar to that of a magazine of an automatic gun. By the time the magazine box is removed from the tool, the cartridge or magazine strip is cut out. It is advantageous when the used portion of the magazine strip can be easily removed only with a partial movement of magazine strip. In this case the magazine strip is cut out by a blade provided on the magazine compartment.
According to a further advantageous embodiment of the present invention, the setting tool has two housing parts movable relative to each other. The two parts can move relative to each other as a result of recoil of the setting tool upon ignition of the propellant charge. According to the invention, the cutting element, e.g., a blade is so arranged on one of the housing parts that it is displaced through the displacement path of the magazine strip in response to movement of the two parts relative to each other which is caused by the recoil of the tool.
A particular advantage of cutting of the used portion of the strip as a result of the recoil of the tool consists in that a user of the setting tool does not need initiate a cutting process after a setting step as the magazine strip is already cut automatically, with the cut-out blisters and/or cartridges falling out.
The adverse effect of recoils on the tool user, and cutting off the magazine strip upon pressing of the tool against an object is prevented by arranging a damping device that can be formed, e.g., of a damping element and a spring element, between the two housing parts for preventing a relative movement therebetween. When one of the housing parts includes a handle, with the use of the dampening device, no additional damping means is needed in the interior of the tool, which simplifies the construction of the setting tool.
Further with the described embodiment, the entire recoiling mass of the tool is used for effecting the cut, which permits to make the tool relatively light.
According to another advantageous embodiment of the present invention, the cutting device comprises a manually actuated actuation lever and a pivotal cutting element that upon actuation of the actuation lever, is displaced through the displacement path of the magazine strip for cutting the used portion of the magazine strip. The actuation lever and the cutting element are brought back into their initial position by an appropriate spring element. With this embodiment, a tool user can effect cutting-off of the used section only then when the suspended portion interferes with the handling of the setting tool.
Advantageously, the actuation lever and the pivotal cutting element are formed as a one-piece part supported on a single pivot axle. The cutting device of this type can be easily manufactured and is relatively inexpensive.
Besides this simple mechanical cutting device, other manually actuated cutting devices without a pivotal lever can be used. E.g., mechanical cutting devices with which the cutting element, e.g., a blade, performs a translational movement through the displacement path of the magazine strip.
According to a further advantageous embodiment of the present invention, the cutting device or at least the cutting element are electronically controlled. The advantage of an electronically controlled cutting element or a complete electronic cutting device consists in that the cutting process can be effected without any physical intervention of a tool user, with the cutting process being controlled in accordance with predetermined criteria. E.g., the following logical condition can lead to the initiation of a cutting process. E.g., the cutting process can be initiated after, e.g., at least an X number of cartridges have been used or fired, after a setting process ends, or upon actuation of a trigger or an actuation button. Such control eliminates excessive cuttings.
According to a further advantageous embodiment of the present invention, an electronic cutting device or an electronically controlled cutting element has an electrical drive, e.g., an electric motor or a solenoid. The electrical drive can be associated with a gear set. Thus, when the electrical drive has a small power capacity and a high-speed motor, a gear set with a high transmission ratio can drive a rotatable cutting element. The control of the electric motor and the transmission ratio can be so selected that a rotatable knife would perform exactly one revolution per cut.
It is advantageous when the cutting element is formed as an eccentrically rotatable cutting body, e.g., as a spiral knife or a spiral blade. Preferably, the rotatable cutting body or the spiral knife has a recess that would permit passing of propellant charges or blister cartridges during displacement of the magazine strip. With this embodiment of a cutting device, complicated movements of the cutting element can be avoided and which otherwise would have to be effected by an appropriate control of the electrical drive.
According to yet another advantageous embodiment of the present invention, the electronically controlled cutting element is formed as a thermal cutting element, e.g., as an incandescent wire or a heatable blade. With such a cutting element, e.g., the incandescent wire, the magazine strip can be melt through at a desired point in time. Advantageously, the thermal cutting element is spring-biased toward the magazine strip. It is further advantageous when a feeler or scanning element, which cooperates with the thermal cutting element, is provided. The feeler element can scan cutting marks provided on the magazine strip. The thermal cutting element or the incandescent wire usually slides over the magazine strip, without being hot, or is spaced by a small distance from the magazine strip. The scanning element or the feeler is usually made of an electrically insulating material and also slides over the magazine strip, which is made of a plastic material, under an action of a biasing force. When a cutting mark which, e.g., coincides with transportation holes provided on the magazine strip, is scanned, the feeler falls into a hole(s), causing lowering of the cutting element. If the cutting element is not under current, i.e., that wire does not glow, the wire would prevent further falling of the feeler into the transportation hole. The magazine strip can be further advanced into a longitudinal direction If a cut should be made, and the wire is hot, the magazine strip would be molten through.
According to a yet another advantageous embodiment of the present invention, the cutting element is formed of two, inclined to each other cutters forming together an angle which is not equal 180xc2x0. With such configuration of the cutter arrangement, with the cutters being inclined toward each other or away from each other, the cutting process can be effected with a smaller expenditure of force that with a cutter(s) not inclined to the magazine strip.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.